1. Field of the Invention
This invention relates to a unique foliar fertilizer formulation, and a method of applying same to field crops, such as legume crops as for example soybean, beans, peas and the like; other dicotyledonous crop plants, such as cotton, tomato, potato and the like; and grasses such as corn (maize), wheat and the like cereal grain crops. More particularly, this invention relates to a foliar fertilizer formulation and a method of applying such formulation which provide for enhanced crop yields.
2. Prior Art
The use of certain six-membered carbocyclic substituted, 1,3-butadiene compounds as plant growth regulants is known. For example, Netherlands Pat. No. 6,703,449 discloses the use of 3-methyl-5-(1-hydroxy-4-oxo-2,6,6-trimethyl-2-cyclohexenyl)-2,4-pentadieno ic acid to induce leaf senescene in sprouts, potatoes and cotton while at the same time stimulating fruit development. Similarly, U.S. Pat. No. 3,499,750 discloses that 3-methyl-5-(1-hydroxy-4-oxo-2,6,6-trimethyl-2-cyclohexen-1-yl)-2,4-pentadi enoic acid can be used to accelerate the ripening of commercially important fruit such as olives, cotton (bolls) and nuts, and Netherlands Pat. No. 6,703,020 discloses thatthis compound can be used to stimulate growth, flowering and defoliation of cotton plants, olive treesand citrus trees. Lastly, U.S. Pat. No. 3,576,839 teaches that six-membered carbocyclic substituted 1,3-butadiene compounds, such as 1-hydroxy-p-2,6,6-tetramethyl-4-oxo-2-cyclohexene-1-penta-2,4-dienoic acidmethyl ester, can be used in pre-emergent herbicidal applications to delay the germination of seeds, and in post-emergent applications to defoliate and to effect leaf senescence.
The effects of plant hormones and growth regulators on solute uptake into plant cells has attracted some attention and both promotive and inhibitory effects have been shown (Encycl. PlantPhysiol., N.S., IIB: 307-342, 1976). The ability of the plant hormone abscisic acid to promote ion flux from the stomatal guard cells has been investigated fairly extensively (An. Rev. Plant Physiol. 31:453-489, 1980). It has also been reported that abscic acid increases the transport of .sup.86 Rb-Rb+ from the primary leaves to the roots of bean plants (Zeitschr Pflanzenphysiol. 78: 95-102, 1976).
In foliar feeding of plants, the nutrients are dissolved in water and the aqueous solution of nutrients is sprayed onto the leaves of the plants. U.S. Pat. No. 3,087,806 describes a method for improving the yield of soybeans by spraying the plants periodically throughout their growth with an aqueous solution of urea phosphate. The patent recommends twice weekly applications, and in an example such twice weekly sprayings were carried out for a period of 18 weeks.
U.S. Pat. No. 3,558,300 describes a method for foliar feeding of field crops, including soybeans and cereal grains, with an aqueous solution of ammonium polyphosphate. Adequate ground fertilizer is employed in conjunction with the foliar feeding. It is claimed that the method improves the stress resistance of the plants. The ammonium polyphosphate solution is described as being applied during the crop growth period up to the flowering period.
U.S. Pat. No. 4,038,064 describes a foliar fertilizer composition containing urea, water, potassium, phosphorus in the form of linear polyphosphates, and micronutrients, such as sulfur, boron, zinc, iron, manganese and copper. The patent also describes a process of improving soybean plant yield by applying the composition to the foliage of the soybean plant. The patent states that the composition must be applied during the period from shortly before flowering to shortly after the beginning of seed fill.
U.S. Pat. No. 4,146,383 describes a method for improving the yield of legume field crops and cereal grain crops by applying a foliar fertilizer composition containing sources of nitrogen, phosphorus, potassium and sulfur to the foliage of the crops during the seed filling period. The patent specifies that prior to the seed filling period, nutrients are supplied to the growing legume and cereal crops exclusively from the ground.
U.S. Pat. No. 4,033,146 describes a method of fertilizing conifer forests with nitrogen containing compounds by direct aerial application to the conifer foliage of an aqueous solution containing a nitrogen source, such as urea, ammonia, and nitrates of ammonium, calcium, and potassium; ammonium phosphates and sulfates; or combinations thereof. The patent states that other micronutrients including iron, manganese, copper and zinc can be added to the solution.
U.S. Pat. No. 4,033,747 discloses a method of fertilizing conifer forest by direct application to the foliage of the conifers of a solution containing a water-soluble nitrogen source. The patent also states that the solution may include sources of calcium, potassium, phosphorus, sulfur and minor trace metal nutrients, such as iron, cobalt, molybdenum, manganese, copper, boron, zinc, magnesium and mixtures thereof.
It has been reported that mixed results have been achieved with foliar fertilization of crops, especially field crops and more particularly soybeans. While some tests suggested that yield improvements could be achieved, others suggested that no improvements at all were realized from foliar application of nitrogen-phosphorus-potassium (N-P-K) solutions. The January, 1969 issue of "World Farming" contains a more complete dissertation of the benefits of N-P-K foliar fertilization and the limits of application level beyond which leaf scorch occurs. Another article reprinted from Ohio Farm and Home Research, Vol. 41, No. 302, September-October, 1956, reports no benefit from foliar application N-P-K solutions.
Unsuccessful attempts to increase crop yield by foliar fertilization have been reported by Mederski and Volk for wheat, corn, soybeans, oats and alfalfa. When the field crops were grown in soils with adequate fertility they failed to respond positively to foliar sprays containing N, P, and K. Mederski, H. J. and Volk, G. W., Foliar Fertilization of Field Crops, Ohio Agr. Exp. Sta. Research Cir 35, (August 1956). It has been generally assumed that legume and cereal grain crops which have adequate soil fertilization will not produce significantly higher yields of the grain by supplemental foliar fertilization, although it has been recognized that the nutrients in the spray are absorbed by the leaves of the plants.
It is believed that the adverse results were due to varying environmental factors, soil fertilizers, to the inability to apply more than small quantities of foliar fertilizers without damaging plant tissue, especially foliage and especially to an inability of the plant to effectuate translocation of foliarly-applied nutrients to those portions of the plant to obtain maximum benefit at a particular growth stage of the plant. For example, early in the vegetative growth stage when foliage or vegetative tissues require significant amounts of nutrients of growth, the normal translocative faculties of the plant do not direct the major portion of foliarly-applied nutrients to those growing tissues. Similarly, during the reproductive stage of growth, it is desirable to direct the majority of foliarly-applied nutrients to the reproductive tissues; however, the normal translocative mechanism of the plant does not comply with this requirement.